In the field of Medical Imaging, one modality is nuclear medicine (gamma camera) imaging. This uses a detector consisting of a scintillator backed by a plurality of photomultiplier tubes (PMTs) with appropriate electronics. A patient is given a radioisotope either by injection or ingestion and the detector(s), after being placed in close proximity to the patient, can determine where the radioisotope goes or has gone.
When the radioisotope emits a gamma photon in the direction of the detector, it is absorbed by the scintillator. The scintillator emits a flash of light (a scintilla) which is detected by one or more of the plurality of PMTs. The PMTs nearest to the flash typically receive a stronger signal than those further away. By measuring the intensity of the flash at each PMT, then performing a calculation, for example a centroid type calculation, a fairly accurate estimation of where the flash occurred is possible.
The output of each of the PMTs is an electrical current proportional to the amount of light detected by the PMT. The PMT output current can be converted into a voltage and amplified and then integrated to derive the total energy (light) detected by each PMT.
Gamma camera systems and methods that can be used with the disclosed invention are described in co-pending U.S. patent applications Ser. No. 11/101,673 filed on Apr. 8, 2005; Ser. No. 11/140,337 filed on May 27, 2005; Ser. No. 11/140,336 filed on May 27, 2005; and Ser. No. 11/171,028 filed on Jun. 30, 2005; and provisional application Ser. No. 60/615,831, filed on Oct. 4, 2004; each incorporated herein by reference for all that they teach.
In nuclear medicine cardiac first pass imaging, dynamic time varying data may be acquired during the first transit of the bolus of an injected radiotracer through the central circulatory system. The planar position of each data event may be recorded with embedded time information or the data may be accumulated into arrays of fixed or varying time. FIG. 1 shows a configuration in which a gamma detector is placed over the chest for imaging use. After the data is acquired and stored, it may be processed within a computer system to provide additional qualitative and quantitative information that may be viewed on a computer system, saved on a storage media for future viewing, and/or captured to an output device for offline viewing. The processing of the data may require a high degree of operator knowledge, skill, and training to provide reproducible and consistent results, and utilize an operator's time that could otherwise be spent elsewhere. Inter- and intra-operator variability may exist so that subsequent data collections and processing provide inconsistent results. Accordingly, a process and device that reduces operator interaction would be beneficial.